Oracle Data Blocks Performance - Quiz

Each question is worth one point. Select the best answer or answers for each question.

1.	Which of the following are true about the PCTFREE parameter? Please select all the correct answers.
	A.	PCTFREE reserves space on the data blocks for row expansion.
	B.	Too small a value for PCTFREE may result in chained rows, causing excessive I/O.
	C.	PCTFREE triggers a freelist re-link operation when the block falls below the threshold.
	D.	The PCTFREE parameter only applies to tables that may have column values expanded with UPDATE statements.

2.	What are some signs that an index may benefit from rebuilding? Please select all the correct answers.
	A.	A large number of deleted leaf nodes
	B.	Excessive index splitting during INSERT operations
	C.	A high ratio of deleted rows to total rows as reported in INDEX_STATS
	D.	A high value for block gets per access

3.	When will reducing the high water mark (HWM) for a table improve performance? Please select the best answer.
	A.	For index range scans after a large number of rows have been deleted
	B.	For any full-table scan regardless of row deletion history
	C.	For index range scans that use multi-block reads
	D.	For full-table scans after a large number of rows have been deleted